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These charts show COVID-19’s resurgence in Mass., and what might come next

Cases are going up. So it's a good time to get one of these.Pat Greenhouse/Globe Staff

Massachusetts coronavirus case counts have rebounded sharply as the supercontagious Delta variant has taken hold. Hospitalizations are moving up, too, though not as dramatically. Deaths remain in the single digits. The question is: What happens next?

With the Bay State a national leader in vaccinations that are highly effective in protecting people from severe illness and death, experts and officials are hoping the deadly virus won’t hit as hard this time around.

Still, they’re urging anybody who remains unvaccinated to get shots. And, as the variant surges across the nation, both state and federal officials have advised people to return to wearing masks in certain situations, even if they’re fully vaccinated.


Dr. Shira Doron, an infectious disease physician who is the hospital epidemiologist at Tufts Medical Center, said she expected that the state’s high vaccination rate would blunt the impact of the case increase, but she added, “This virus always surprises me.”

“The Delta variant is much more contagious. It is a game-changer in that sense. We are lucky in Massachusetts that we are not seeing the kind of tragedy that people are seeing in other parts of the country and the world. Vaccination is the most important way to protect yourself and the people you love,” she said.

Dr. Howard Koh, a professor at the Harvard T.H. Chan School of Public Health, said in an e-mail, “The Delta variant has dramatically upended recent progress against the pandemic and is forcing a reset everywhere. Despite nationally leading vaccination rates in Massachusetts, we have to drive them up even further. We must stay humble and prepare for the worst while hoping for the best.”

Here’s a roundup of some key coronavirus charts that show where we stand in the battle against the pandemic. The data is current as of the end of Wednesday.



Things were looking rosy for the state when the seven-day average of reported cases hit a low of 52 a day on June 28. Those were the days. The seven-day average is now 784 a day, more than 15 times higher.

Cases overall

Let’s zoom out and take a look at the numbers from the beginning of the pandemic. The chart shows the numbers are on the rise, but still a far cry from the 6,100 a day seen during the height of the second surge early this year.


How many people are getting so sick from the coronavirus now that they require hospitalization? The number bottomed out at 80 on July 4 and is now up to 245, more than three times higher. Hospitalizations tend to lag behind case counts, which raises the possibility these numbers will go up in the coming days.

Hospitalizations overall

The longer-range chart, which shows hospitalizations from the beginning of the pandemic, illustrates again that the numbers are growing but are still nowhere near those seen in the spring 2020 surge and the surge this past winter.


The number of daily deaths reported from the coronavirus slowed to a trickle by mid-July. On at least two days there were zero coronavirus deaths reported. The seven-day average has been edging up since then. It reached five a day last week before subsiding to slightly less than three a day on Wednesday.

Deaths tend to lag behind hospitalizations, so these numbers may not reflect the full toll of the current cases for a few weeks.


MWRA wastewater data

The levels of coronavirus in the wastewater at the Massachusetts Water Resources Authority’s Deer Island treatment plant, considered a harbinger of future cases, have generally been on the rise.

The pilot program looks for SARS-CoV-2 RNA copies per milliliter of waste water. Cambridge-based Biobot Analytics, which conducts the testing, says it has found that the amount of virus in the waste water is correlated with newly diagnosed coronavirus cases four to 10 days later.

The MWRA reports numbers for tests of waste water coming in from the northern section of the system, which includes Boston, and the southern section.

In a possible glint of good news, the coronavirus in the samples from the northern section of the system have ticked downward in the past few days. The levels for the southern system saw a tiny downtick in the most recent day’s data.


While the climbing lines on the charts may give the average person an unwelcome flashback to earlier devastating surges of the pandemic that has killed around 18,000 people in the state, there is some good news: Many residents have gotten the highly effective vaccines.

Seventy-three percent of the total population and nearly 85 percent of adults have received at least one vaccine shot, according to the US Centers for Disease Control and Prevention. The national average is 58 percent and 70 percent, respectively. Some states are lagging behind — and experiencing major surges.


In Massachusetts, efforts continue to convince the holdouts to get their jabs and raise the state’s numbers even further.

Dr. Ashish Jha, dean of the Brown University School of Public Health, told New York Times columnist Ezra Klein that in highly vaccinated places, hospitalizations and deaths would not follow cases the way they have in the past.

“Even in highly vaccinated states, unvaccinated people cluster,” Jha told Klein. “So you will see the initial rise, but once that cluster starts bumping into immunity, it won’t be able to sustain itself. We’ll find that out in the next couple of weeks in places like San Francisco and Boston.”

Dr. Paul Sax, clinical director of the Division of Infectious Diseases at Brigham and Womens Hospital, said the hope is that case counts will “decouple” from severe illness due to a “combination of the vaccines (breakthroughs are milder) and natural immunity (partial protection from reinfection).

“This is what happened in the United Kingdom,” he said.

“The problem,” Sax said in an e-mail, “is that people who don’t respond to the vaccine — for example, those with weakened immune systems — and people who still haven’t been immunized obviously get very sick from COVID-19. This is what’s happening in states like Louisiana, Missouri, and others with low vaccine rates.”

“This is why we must get as many people vaccinated as fast as possible,” he said.

Martin Finucane can be reached at martin.finucane@globe.com.